The Chemistry of Powder and Explosives - Sciencemadness Dot Org

ROGER BACON 37
large as the human thumb. From the force of the salt called
saltpeter so horrible a sound is produced at the bursting of
so small a thing, namely a small piece of parchment, that we
perceive it exceeds the roar of sharp thunder, and the flash
exceeds the greatest brilliancy of the lightning accompanying
the thunder. 11
A description in cypher of the composition of black powder in
the treatise "De nullitate magiae" 12 which is ascribed to Roger
Bacon has attracted considerable attention. Whether Bacon wrote
the treatise or not, it is certain at any rate that the treatise dates
from about his time and certain, too, that much of the material
which it contains is to be found in the "Opus Majus." The author
describes many of the wonders of nature, mechanical, optical,
medicinal, etc., among them incendiary compositions and firecrackers.
We can prepare from saltpeter and other materials an artificial
fire which will burn at whatever distance we please.
The same may be made from red petroleum and other things,
and from amber, and naphtha, and white petroleum, and
from similar materials. . . . Greek fire and many other combustibles
are closely akin to these mixtures. . . . For the
sound of thunder may be artificially produced in the air with
greater resulting horror than if it had been produced by natural
causes. A moderate amount of proper material, of the
size of the thumb, will make a horrible sound and violent
coruscation.
Toward the end of the treatise the author announces his intention
of writing obscurely upon a secret of the greatest importance,
and then proceeds to a seemingly incoherent discussion of something
which he calls "the philosopher's egg." Yet a thoughtful
reading between the lines shows that the author is describing the
purification of "the stone of Tagus" (saltpeter), and that this
material is somehow to be used in conjunction with "certain parts
of burned shrubs or of willow" (charcoal) and with the "vapor of
pearl" (which is evidently sulfur in the language of the medieval
""The Opus Majus .of Roger Bacon," trans. Robert Belle Burke, University
of Pennsylvania Press, Philadelphia, 1928, Vol. 2, p. 629.
12 Cf. "Roger Bacon's Letter Concerning the Marvelous Power of Art
and of Nature and Concerning the Nullity of Magic," trans. Tenney L.
Davis, Easton, Pennsylvania, 1922.